Not sure what you are regarding to when you ask about support, database support is something completely different and if you want to be able to use EF or nHibernate is up to you to encapsulate into your project. I personally use EF and it works
fine. You could create a concrete instance and pass it around with DI as with any framework. This framework uses MEF extensively for the WPF/Silverlight flavors, but has the option to allow for other containers to be used.